Where Class 10 students lose marks in Science

The lowest-scoring chapter was Light - Reflection and Refraction: students scored 37% of the marks on its questions, against 49% across the whole paper.

What examiners look for: Examiners mark this chapter point by point: the law or definition, the labelled diagram, the equation with units. Revise it from the marking schemes of past papers and practise writing each point in full, not just reading it.

Electricity cost the most marks overall: 22% of all the marks lost, with 45% scored on its questions.

What examiners look for: A chapter that turns up in most papers and costs this many marks repays a full revision cycle: work through its past-paper questions against the marking scheme until you can write each answer, with every step, without notes.

Students scored 66% on 1-mark questions but only 44% on questions worth 5 marks or more, which made up 21% of all the marks lost.

What examiners look for: Long answers are marked step by step. Plan the answer before writing, cover every part the question asks for (a), (b), (c), and show the working: each correct step earns its own mark.

No answer was found for 7.5% of the questions, and these blanks made up 18% of the marks lost. (This includes answers we could not locate on the sheet, for example where the question number was missing.)

What examiners look for: CBSE board papers have no negative marking, so a blank answer is the only sure zero. Attempt every question, and write the question number clearly next to each answer so it is found and marked.

Where the checker recorded why a written answer (2 marks or more) lost marks, the most common reason was "calculation or careless slip" (55%), then "question misread" (32%).

What examiners look for: Carry units through every line, re-check the arithmetic in the last two minutes, and box the final answer: a correct method still earns marks even when the arithmetic slips.